This figure illustrates how task considerations enforce automation.

The figure is of a boiler controlled using an On-Off switch.

If the boiler is safety critical, then an operator should be dedicated to the boiler operation, to identify situations of overheating.

To enable control, the boiler should be equipped with a means to indicate the operators about situations of overheating.

Because the operators might not notice the indication, the indication should be replace with an alarm. Yet, the operator might miss the alarm for various reasons.

The solution is by automation. In this example, the conventional solution is by adding a thermostat, to control the heating.

Automation removes the operators from the control loop, featuring more reliable control.

However, the operators still need to stay in an outer loop, as a supervisor.  

Updated on 21 Jul 2016.